EPSC Abstracts Vol. 11, EPSC2017-881-1, 2017 European Planetary Science Congress 2017 EEuropeaPn PlanetarSy Science CCongress c Author(s) 2017

Impact Effects Calculator. Orbital Parameters. S.A. Naroenkov(2), D.O. Glazachev(1), A.P. Kartashova(2), I.S. Turuntaev(1), V.V. Svetsov (1), V.V. Shuvalov(1), O.P. Popova(1) and E.D. Podobnaya(1) (1)Institute for Dynamics of Geospheres RAS, Moscow, Russia ([email protected] / Fax: +7-499-1376511), (2)Institute of Astronomy RAS, Moscow, Russia

Abstract the ground, formation of craters and plumes are simulated. Results obtained in these simulations will Next-generation Impact Calculator for quick be used to get interpolations for rapid assessment of assessment of impact consequences is being prepared. the impact effects. As an example, in the calculator [3] The estimates of impact effects are revised. The thermal damage from crater-forming impacts is possibility to manipulate with the orbital parameters considered based on nuclear explosions results and and to determine impact point is included. crater plume luminous efficiency estimates but the radiation from the objects decelerated in the atmosphere is not included [3]. For our calculator, the Introduction systematic modeling of the entry of asteroidal and The population of near-Earth objects (NEOs, both cometary bodies of various sizes (20-3000 m), asteroids and comets) contains a wide variety of including the determination of thermal fluxes and bodies with diverse physical and dynamical properties, exposures, was carried out [5], and scaling relations and presents a permanent threat to our civilization [1]. for thermal fluxes on the ground were found [6]. These The number of undiscovered potentially hazardous and other similar scaling relations will be used for fast asteroids with sizes from 140 meters to 1km is online estimates of impact effects in our calculator. estimated as about 20 000 objects, the number of These relations are dependent only on cosmic body potentially dangerous bodies with sizes from 50 m to density, size, velocity and angle of entry. 140 m is estimated to exceed 200 000 objects [2]. The recent Chelyabinsk event demonstrated that even a To predict impact effects in any location one must small object, only 20 m in diameter, has enough determine the place of the impact (or the point of energy to cause considerable destruction of property. maximum energy deposition) or to find it based on suggested orbital parameters of the impacting object. So we decided to include an orbital block into our 1. Impact calculator calculator. Detection of new objects proceeds continuously. The characteristics and orbital parameters of an already 2. Orbital characteristics and discovered body are also regularly refined. For any impact point discovered object it is necessary to assess the potential risk and damage resulting from the possible collision Our impact consequences calculator allows to create a of such body with the Earth. Physical processes, which virtual (hypothetical) orbit of the celestial body, which occur during the impact, are complex and their will lead to a collision with the Earth. The impact point simulations are time consuming. An instrument for may be determined based on this orbit. The creation quick estimation of the consequences of a comet or of a virtual orbit can be realized by two ways. asteroid impact on the Earth is needed. Such Web- based calculator was created by Collins et al [3]. In the first way, the user, setting five parameters of the Keplerian orbit, the date of collision, the size of the We are going to elaborate the next generation version object, creates a dangerous orbit and collision of an impact calculator. Extensive numerical conditions. For the first method, the place, speed and simulations of impacts are carried out using a energy of the collision are predicted. The second way hydrodynamic model, equations, and a numerical allows to predict a dangerous orbit based on the time technique described, e.g., in [4]. It is assumed that the and place of collision, the angle of entry into the cosmic object has no strength, deforms, fragments, atmosphere, the direction and speed of the impact. We and vaporizes in the atmosphere. After the impact on

believe that both possibilities can be interesting and in [3] Collins G.S., Melosh H.J., Marcus R. (2005) Earth demand. Impact Effects Program: A Web-based computer program for calculating the regional environmental consequences of To determine the orbit, a numerical model is used, a meteoroid impact on Earth // Meteorit. Planetary Sci. V. 40. Nr.6. P.817-840 which takes into account perturbations from the Earth, the Moon, the Sun, the rotation of the atmosphere, and [4] Shuvalov, V.V., Svettsov, V.V., Artem’eva, N.A., the resistance of the atmosphere. This numerical Trubetskaya, I.A., Popova, O.P., and Glazachev, D.O.: model was tested at the orbits of such bodies as the Asteroid Apophis: Evaluating the impact hazards of such Chelyabinsk meteorite [7], 2008 TC3, Novato bodies, Sol. Sys. Res., Vol. 51, pp. 44-58, 2017. meteorite [8], meteoroid 2014 AA. [5] Svetsov, V.V., Shuvalov V.V.: Thermal radiation from For the parameters of Chelyabinsk meteoroid orbit [7], large bolides and impact plumes. Abstract (this conference). we determined the flight trajectory. The coordinates of the largest meteorite fall site were compared with the [6] Glazachev D.O., Popova O.P., Podobnaya E.D., Svetsov projection of our predicted trajectory on the Earth’s V.V. and Shuvalov V.V.: Radiation and ablation of large surface. The distance between the fall and our meteoroids decelerated in the Earth’s atmosphere. Abstract trajectory was 600 meters. These results confirmed the (this conference). correctness of the numerical model for the orbit and [7] Emelyanenko V.V., Naroenkov S.A., P. Jenniskens, O. the impact point determination. We also studied the P. Popova. The orbit and dynamical evolution of the circumstances of the fall of known asteroids, which Chelyabinsk object. // Meteoritics & Planetary Science, can hypothetically collide with the Earth. For the study, 2014, V. 49, Is. 11, p 2169- 2174 27 near-Earth asteroids were selected, in which the minimum distance between the orbit of the asteroid [8] Jenniskens, P et al,. Fall, recovery, and characterization and the orbit of the Earth is less than 6378 km. We of the Novato L6 chondrite breccia. METEORITICS & determined that most of the collision occurs at speeds PLANETARY SCIENCE, Volume: 49, Issue: 8 Pages: of 15 to 25 km/sec, the angle of incidence on average 1388-1425 is 45 degrees. 3. Summary Next-generation Impact Calculator for quick assessment of impact consequences is being prepared. The estimates of impact effects are revised. The possibility to manipulate with the orbital parameters and to determine impact point is included.

Acknowledgements This work was supported by the Russian Science Foundation, project no. 16-17-00107. References

[1] Harris A. W., Boslough M., Chapman C. R., Drube L., Michel P., and Harris A. W. (2015) Asteroid impacts and modern civilization: Can we prevent a catastrophe? In Asteroids IV (P. Michel et al., eds.), pp. 835–854. Univ. of Arizona, Tucson.

[2] Committee to review near-Earth object surveys and hazard mitigation strategies. Defending planet Earth: Near- Earth object surveys. The National Academies Press, 152 p. 2010.